Sales tax calculation when there are multiple invoices prior to shipment

I hope I stated my issue correctly above.  We are trying to figure out how to properly enter taxes on an invoice where we have partially invoiced but sales tax would not be applied until shipment has been made and the final invoice issued.  This is fairly common for us as we don’t always know the location of shipment prior to those final invoices (we are an Oil & Gas equipment manufacturer and our equipment will be sent to multiple locations in an oil field(s) ).  We are trying to figure out how to get the full amount of tax properly reflected on that final invoice.